Star Cup: What is the legend season?

Once you are promoted to this tier, you can join the 2 week legend season where players around the world fight for top position in the leaderboard. You have to play one challenge to enter into the season. You will be rewarded based on your final standing in the leaderboard at the end of the season. Additionally, all legends are lowered to 500 stars to give a fresh start to every season. However, your personal best (highest number of stars in a season) is always featured in your legend board.